const Vertex = require('merkle-trie')
const Store = require('merkle-trie/store')
const U256 = require('./deps/u256.js')
const Address = require('./deps/address.js')
const Block = require('./deps/block.js')
// TODO remove fakeblockchain
const fakeBlockChain = require('./fakeBlockChain.js')

module.exports = class Environment {
  constructor (data = {}) {
    const defaults = {
      block: new Block(),
      blockchain: fakeBlockChain,
      // gas tank
      gasPrice: 0,
      gasLeft: 1000000,
      gasRefund: 0,
      // call infromation
      address: new Address('0x0000000000000000000000000000000000000000'),
      origin: new Address('0x0000000000000000000000000000000000000000'),
      caller: new Address('0x0000000000000000000000000000000000000000'),
      callValue: new U256(0),
      callData: new Uint8Array(),
      // the ROM
      code: new Uint8Array(), // the current running code
      // output calls
      logs: [],
      selfDestruct: false,
      selfDestructAddress: new Address('0x0000000000000000000000000000000000000000'),
      // more output calls
      returnValue: new Uint8Array(),
      state: new Vertex({store: new Store()})
    }
    Object.assign(this, defaults, data)
  }

  isAccountPresent (address) {
    // const account = this.state.get(address.toString())
    // if (account) {
    //   return true
    // } else {
    //   return false
    // }
  }

  getBalance (address) {
    // const account = this.state.get(address.toString())
    // if (account) {
    //   return account.get('balance')
    // } else {
    //   return new U256()
    // }
  }

  getCode (address) {
    // const account = this.state.get(address.toString())
    // if (account) {
    //   return account.get('code')
    // } else {
    //   return Uint8Array.from(new Buffer([]))
    // }
  }

  async getBlockHash (height) {
    const block = await this.blockchain.getBlock(height)
    return block.hash()
  }

  set createHandler (value) {
    this.createhandler = value
  }

  set callHandler (value) {
    this.callhandler = value
  }

  // kernal
  create (code, value) {
    // STUB
    return [ 1, Address.zero() ]
  }

  call (gas, address, value, data) {
    // FIXME: create a child environment here
    const ret = this.root.messagehandler({
      from: this.address,
      to: address,
      gasLimit: gas,
      value: value,
      data: data
    })
    return [ !!ret.executionOutcome, ret.returnValue ]
  }

  callCode (gas, address, value, data) {
    // STUB
    return [ 1, new Uint8Array() ]
  }

  delegateCall (gas, address, data) {
    // STUB
    return [ 1, new Uint8Array() ]
  }
}